409645 has 4 divisors (see below), whose sum is σ = 491580. Its totient is φ = 327712.

The previous prime is 409639. The next prime is 409657. The reversal of 409645 is 546904.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 116964 + 292681 = 342^2 + 541^2 .

It is a cyclic number.

It is not a de Polignac number, because 409645 - 2⁷ = 409517 is a prime.

It is a super-3 number, since 3×409645³ = 206226385398033375, which contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40960 + ... + 40969.

It is an arithmetic number, because the mean of its divisors is an integer number (122895).

2⁴⁰⁹⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

409645 is a deficient number, since it is larger than the sum of its proper divisors (81935).

409645 is an equidigital number, since it uses as much as digits as its factorization.

409645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81934.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 409645 is about 640.0351552845. The cubic root of 409645 is about 74.2681409192.

The spelling of 409645 in words is "four hundred nine thousand, six hundred forty-five".